Lucas said, “I’m really proud of the party’s progress under our co-leadership. We have more councillors in more communities than ever before, we’ve put forward our boldest ever policies and we’ve challenged and weakened this callous Tory government.

"We’ve also started an internal party review that is already paying dividends – and will make the party more inclusive in its makeup and an even more successful electoral force.”

Nominations for leadership and senior positions will be held during June, and the vote will take place in August.

Lucas said: “I won’t be seeking nominations to be a candidate in this year’s leadership election when the process starts on Friday – but instead will be focusing even more on work in Parliament and in Brighton. I believe that Jonathan and I have shown the power of working together and that it’s now time for me to show the power of letting go.”

Lucas also wrote a piece in the Guardian explaining her decision to step down.

“I hope I’m continuing to show the kind of leadership that’s about doing what’s best for the party by creating space now for more voices to be heard,” she wrote in the article.